30 ABSORPTION. 



quence of which the constituents may be more its surface the solution of some narcotic or 



completely mixed together, and to a certain poisonous substance, the effects of which were, 



degree of pressure and temperature to which it in a short time, manifested in the system at 



is exposed, which may modify any spontaneous large.* 



change that might otherwise take place in the This doctrine of imbibition and^ transudation 

 arrangement of its elements. But to whatever has been embraced by M. Fodera, who has 

 cause it may be referred, we must consider the endeavoured to confirm the opinion of M. Ma- 

 chemical and physical change in the nature of gendie by additional experiments, which he 

 the chyle as one effect produced by the lacteals, conceives tend directly to prove that the vessels 

 as well as the progressive motion which is im- of the living body possess this power of im- 

 parted to their contents. bibition. The method which he adopted to 



In the present state of our knowledge on the prove this point, in the most unequivocal man- 

 subject, it remains for us to consider whether ner, was to inject into two separate cavities of 

 we have any independent evidence of the exist- the body two fluids, which by their union pro- 

 ence of the muscular fibres of the absorbent duce a compound, the presence of which may 

 vessels, whether, if their existence be proved, be easily detected, and which could be formed 

 and their contractility thus established, it by no other means except by this union. For 

 would be necessary for us to search out for example, into the cavities of the pleura and 

 other causes of the effects, and lastly, to what the peritoneum were respectively injected the 

 other principle the acknowledged effects might solutions of the ferro-prussiate of potash and of 

 be attributed, should it appear, upon full con- the sulphate of iron, when it was found, after a 

 sideration, that the assigned cause is insufficient certain length of time, that various membranes 

 or inadequate. and glands, connected with the thorax and the 



The above considerations lead us to give an abdomen, were tinged with a blue colour, 

 account of the hypothesis of the action of the M. Magendie afterwards performed an ex- 

 absorbents, which has been proposed by M. periment, which seemed more directly to bear 

 Magendie. He had ascertained, by a previous upon the question, where a solution of the 

 train of experiments, that according to the con- ferro-prussiate was retained in a portion of the 

 dition of the system as to depletion or plethora, intestine, at the same time that its external 

 the process of absorption was respectively acce- surface was placed in contact with a solution 

 lerated or retarded. Hence he draws the con- of the sulphate of iron: the part was then ex- 

 clusion, which, however, we conceive not to be posed to the galvanic influence, the result of 

 a necessary consequence of the premises, that which was that a blue tinge was communicated 

 the function depends on a mere mechanical to the sulphate. We are further informed, that 

 principle, independent of any vital action. The according to the direction of the galvanic cur- 

 mechanical principle to which he has recourse, rent, the blue colour was produced either in 

 and which he thinks can alone account for the the sulphate or in the ferro-prussiate. From 

 effect, is that of capillary attraction ; but this he these experiments M. Fodera draws the con- 

 conceives not to take place from the open elusion, that the processes of absorption and of 

 mouths of the vessels, according to the ordinary exhalation may be referred to the mechanical 

 conception of the subject, but that the fluid is operations of imbibition and transudation, which 

 imbibed by the substance of the vessel itself, take place through the pores or capillary open- 

 and is, as it were, filtered through its pores.* ings of the various textures of the body.f 

 He explains its further progress by supposing, On these experiments, and the conclusion 

 that when it has entered these pores, it is car- deduced from them, we shall remark, that the 

 ried forwards by the current of the fluid pre- facts appear to prove that membranes, perhaps 

 viously in the vessel. during life, and certainly after death, before 



To prove his idea of the permeability of the any visible decomposition has taken place, are 



parietes of the vessels, he instituted a series of capable of transmitting fluids through their tex- 



experiments on the veins of an animal shortly ture ; but we conceive that the analogy between 



after death, when he found that they were this case and that of the entrance of chyle into 



capable of imbibing and transmitting certain the lacteals is so incomplete, that we can draw 



fluids with which they were placed in contact, no inference from the one of these events which 



Still farther to substantiate the hypothesis, can be fairly applied to the other. Both the 



M. Magendie repeated a set of analogous ex- mechanical and the physiological properties of 



periments on the vessels of a living animal, membranes and vessels differ much from each 



They consisted essentially in detaching a por- other, while the nature of the fluids employed in 

 tion of one of the gre*t veins, and applying to 



* Journ. t. i. p. 9, 10. 



* Journ. t. i. p. 6 et seq. and Diet, de Med. t " Recherches sur PAbsorptionet 1'Exhalation/' 



et Chir. Prat. "Absorption," t. i. p. 91 et seq. and Magendie's Journ. t. iii. p. 35 et seq. ; see, also 



The doctrine of transudation was maintained by Med. Repos. v. xix. p. 419, et Med. Journ. v. xix. 



many of the older physiologists; see Kauw Boer- p. 488, 9. On this subject see the remarks of 



haave, de Persp. ; also Haller, El. Phys. ii. 2. 23 ; Tiedemann, Traite de Physiol. par Jourdan, $ 168. 



more lately it was supported by W. Hunter, Med. p. 242. Mr. Mayo remarks, that the principle of 



Com. ch. 5; by Walter, ubi supra, 28 . . 35 ; and imbibition and transudation affords a more easy ex- 



by Mascagni, ps. 1. sect. i. and is zealously main- planation of the experiments of MM. Magendie 



tained by his commentator Bellini, t. i. not. 4. and Segalas, than that of venous absorption ; Phy- 



p. 33 . . 0. The " penetrabilite" of the cellular tex- siol. (3rd ed.) p. 97 et seq. See the remarks and 



tnre was one of the fundamental doctrines of Bordeu, objections of Sir D. Barry, Exper. Researches, 



Recherches sur le Tissue muqueux, $ 72. p. 80 . . 2 et alibi -, also Elliotson's Physiol. p. 133. 



